Hydraulic machine having an intake manifold located at the top

ABSTRACT

The invention relates to a hydraulic machine having turbines or a pump turbine, comprising an impeller that is mounted such as to be rotatable about a vertical axis of rotation and has a plurality of blades, an inlet spiral that surrounds the impeller in an annular manner and has a circular outlet opening on the inner circumferential ring thereof, a distributor and/or closure device for adjusting the inflow into the impeller, and an intake manifold for guiding of the water flowing out of the impeller. The intake manifold is arranged above the impeller. At least a bypass pipe can be provided for bypassing the distributor and/or closure device, which bypass pipe connects the inlet spiral directly to the impeller when a bypass valve arranged in the run of said bypass pipe is opened. Furthermore, at least one drainage pipe can be provided for draining the impeller, which drainage pipe connects the impeller directly to a pump sump when a drainage valve arranged in the nm of said drainage pipe is opened. The invention also relates to a method for filling and draining such a machine, and to the preferred use thereof.

The invention relates to a hydraulic machine, especially a pump turbine according to the preamble of claim 1 or 2. The invention further relates to a method for filling or discharging such a machine according to claim 6 or 7 and its preferred use according to claim 9.

Pump turbine systems used in hydroelectric power plants have two operating modes, namely a turbine mode and a pump mode. In the latter, the pump pumps water from a lower basin into an upper basin and is driven for this purpose by an electrical machine which is in drive communication with the pump. The electrical machine is fed from a public power supply grid, i.e. it is supplied with electrical power. In turbine mode on the other hand, the water flowing from the upper basin through the turbine into the lower basin drives the turbine which transmits a corresponding power to the electrical machine. The electrical machine converts the drive power into electrical power and feeds this into the power supply grid. The electrical machine thus operates on one occasion as a generator and on another occasion as a motor. It is therefore also designated as a motor-generator.

In contrast to the aforesaid generic pump turbine systems, reversible pump turbine systems have also become known in which the turbine and pump are formed by a common blade wheel so that in turbine mode the common blade wheel is acted upon with water from the upper basin to generate electrical power and in pump mode it is driven by the electrical machine.

Since such pump storage power plants are used to compensate for load peaks in the power supply grid, the pump turbine must be put into a position to deliver turbine power as rapidly as possible in order to support the power supply grid or to rapidly receive pump power in order to be used for primary grid regulation. It is therefore desirable that the pump turbine of a pump storage power plant can be put into pump mode as rapidly as possible and conversely.

In the transition from the operating mode of phase shifting to the operating mode of pump or turbine operation, it is necessary to fill the drained blade wheel. The draft tube bend is usually located at the bottom, so that the water level can be lifted until complete discharging by purposeful ventilation. If the draft tube bend is situated above the pump on the other hand, its rapid filling would lead to uncontrolled filling of the blade wheel however.

It is now advantageous for a smooth filling process if the rotating blade wheel is filled to the highest possible extent by the headwater pressure from the high-pressure side. This is usually no problem in the case of a conventional arrangement of the draft tube bend because the air in the draft tube bend would not escape. In the case of a draft tube bend situated at the top however, the entire air would escape immediately during opening of the closing valve on the tailwater side, so that controlled filling would no longer be possible. The opening of a closing valve on the high-pressure side such as a guide apparatus, a ring gate, a rotary valve or the like would lead to a considerable safety risk if the closing valve on the tailwater side was simultaneously kept closed. This would lead to the likelihood that the entire draft tube bend would be subjected to the high headwater pressure if load shedding occurred for example during the filling process in which the tailwater closing valve was still closed.

On the other hand, it is necessary during the transition from the operating mode of pump operation to the operating mode of phase shifting to discharge the filled blade wheel. The draft tube bend is usually situated at the bottom, so that the water level can be lowered in a controlled fashion by means of purposeful aeration. This was not possible until now by a draft tube bend situated above the pump.

It is the object of the present invention to solve the problems as mentioned above and to provide a pump turbine system which permits a controlled, rapid and reliable filling of the blade wheel from the high-pressure side with a draft bend tube arranged above the blade wheel without giving rise to the likelihood that the draft tube bend is subjected to the high headwater pressure. At the same time, this solution shall be easy to implement and to be realized at low cost.

This object is achieved by a pump turbine according to the characterizing features of claim 1 and claim 5.

It is a relevant feature of the system in accordance with the invention that the draft bend tube is arranged above the blade wheel and at least one bypass pipe is provided for bypassing the guide and/or closure apparatus, which bypass pipe connects the inlet spiral directly to the blade wheel when a bypass valve arranged in the run of said bypass pipe is opened. The blade wheel can be filled in a purposeful way by these bypass pipes by bypassing the closed guide and/or closure apparatus. It is thus possible by providing the system with a ring gate for example to keep the inlet spiral continuously subject to the headwater pressure, which considerable increases the operational lifespan and further minimizes the times required for operational transitions, since the spiral need not be filled or discharged. There can be one or several of the bypass pipes, which after the closing valves is opened directly into the machine before or after the guide apparatus, preferably into the lateral space of the blade wheel, so that the flow channel is not disturbed by installed parts or openings. A bypass pipe ideally opens into an upper and/or lower turbine or pump cover. The bypass pipes can also be arranged in the annular space between the ring gate and the guide apparatus. In this case, the guide apparatus can be closed for discharging/aerating or filling/ventilating, or it can be larger in an intermediate position than in the closed position.

The bypass pipe can directly be connected to the inlet spiral via a valve. Preferably, the cross-section of the bypass pipe is chosen smaller than the cross-section of the ventilation pipe in the draft bend tube, so that in the case of load shedding for example during the filling process no impermissible pressure increase can occur in the draft bend tube. The valve in the bypass pipe must be locked in such a way that it can only be opened after the opening of the ventilation valve in the draft bend tube and is already closed before the closing of the ventilation valve.

The pump blade wheel can be filled via the bypass pipe during the operation of the machine as is possible by the headwater pressure. The small remainder can be filled from the suction side.

It is a further relevant item of the system in accordance with the invention that the draft bend tube is arranged above the blade wheel and at least one discharge pipe is provided for discharging the blade wheel, which connects the blade wheel directly to a pump sump when a discharge valve arranged in the course of this discharge pipe is opened. The blade wheel can thus be drained when the closing valves on the tailwater side and the headwater side are closed.

The arrangement in the lateral space of the blade wheel prevents the positioning of installed parts or openings in the flow channel. There also may be several discharge pipes, ideally on the bottom, upper or both turbine or pump covers. Preferably, they have a smaller cross-section than the aeration pipes, so that no negative pressure is produced in the blade wheel space which would counteract continuous discharging.

Discharge pipes lead to the pump sump. As a result of the arrangement of the discharge pipes in the lateral space of the blade wheel, it is further possible to utilize the full pump pressure for discharging, so that discharging periods can be minimized. As a result of the arrangement in the lateral space of the blade wheel, a ring gate can simultaneously be used for example to separate the blade wheel space from the spiral so that the inlet spiral does not require discharging.

The system in accordance with the invention is not principally limited to the sole attachment of one type of pipe, but may comprise any desired number and combination of both bypass pipes and discharge pipes as required.

The present invention will be explained below in closer detail by reference to an embodiment shown in the enclosed drawings. The same or similarly acting parts are provided the same reference numerals. The drawings show as follows:

FIG. 1 shows a side view of a pump turbine of Francis configuration in accordance with the invention, comprising a blade wheel which is rotatably held about a rotational axis, and an inlet spiral which surrounds said blade wheel in a ring-like manner, and a draft bend tube situated above the blade wheel, and

FIG. 2 shows an intersected side view of a part of the pump turbine in accordance with the invention according to FIG. 1 in order to illustrate the position of the bypass pipes and the discharge pipes.

FIG. 1 shows a side view of a pump turbine 10 of Francis configuration in accordance with the invention, comprising a blade wheel 20 (not shown) which is rotatably mounted about a rotational axis R, and an inlet spiral 30 which surrounds said blade wheel 20 in a ring-like manner, and a draft tube bend 50 which is situated above the blade wheel 20. In such a pump turbine 10, the water flows into the blade wheel 20 radially to the rotational axis R from an outlet opening present on the inner circumference of the inlet spiral 30. In the blade wheel 20, the water is deflected upwardly under the release of energy in the direction of the rotational axis R, while the blade wheel 20 is made to rotate. The water is then supplied via the draft bend tube 52 to a draft tube connected thereto (not shown).

It is now necessary to fill the discharged blade wheel in the transition from the operating mode of phase shifting to the operating mode of pump turbine operation. The draft tube bend is usually situated at the bottom, so that the water level can be lifted until complete discharging by purposeful ventilation. If the draft tube bend is situated above the pump on the other hand, its rapid filling would lead to uncontrolled filling of the blade wheel however.

On the other hand, it is necessary during the transition from the operating mode of pump operation to the operating mode of phase shifting to discharge the filled blade wheel. The draft tube bend is usually situated at the bottom, so that the water level can be lowered in a controlled fashion by means of purposeful aeration. This was not possible until now by a draft tube bend situated above the pump.

FIG. 2 shows an intersected side view of a part of the pump turbine 10 in accordance with the invention according to FIG. 1 in order to illustrate the position of the bypass pipes 60.1, 60.2 and the discharge pipes 70.1, 70.2. The bypass pipes 60.1, 60.2 bypass a guide and closure apparatus 40 and open into a bottom and upper turbine or pump cover. The guide and closure apparatus 40 can consist of guide blades 40.1 and a ring gate 40.2. In the case of a closed ring gate 40.2 for example, the blade wheel 20 can thus be filled in a virtually rapid and continuous manner from the high-pressure side, wherein the air is discharged via a ventilation pipe (not shown). The cross-sections of the bypass pipes 60.1, 60.2 are preferably smaller than those of the discharge pipes in order to prevent overpressure in the blade wheel space.

Conversely, the blade wheel 20 can be discharged via the discharge pipes 70.1, 70.2 in the case of closing valves which are closed on the high-pressure and low-pressure side, wherein an aeration pipe (not shown) is opened. The cross-sections of the discharge pipes 70.1, 70.2 are also preferably smaller than those of the aeration pipes in order to prevent negative pressure in the blade wheel space.

Both the bypass pipes 60.1, 60.2 as well as the discharge pipes 70.1, 70.2 are equipped with valves which enable reliable opening and closing. Both types of pipes can be implemented easily from a constructional standpoint and can therefore be realized at low cost. The valves can consequently be triggered depending on other closing valves on the high-pressure and low-pressure side, e.g. by means of computer-implemented or numerical controls in order to perform filling the blade wheel 20 with water or discharging the same. The spiral 30 need not be relieved and is drained in any of the two cases, which represents a considerable reduction in the time used for changing over between phase shifting and pump or turbine operation. At the same time, the operational lifespan of the pump turbines will increase considerably.

Although the present invention was described with reference to a pump turbine, it can principally also be realized only in a pump or only in a turbine if rapid filling or drainage is required. The advantages in accordance with the invention can also be observed therein. Adaptations to the cross-section and the number and combination of bypass pipes and discharge pipes required in the special case are included in the knowledge and expertise of the person skilled in the art.

LIST OF REFERENCE NUMERALS

-   10 Pump turbine -   20 Blade wheel -   30 Inlet spiral -   40 Guide and/or closure apparatus -   40.1 Guide blades -   40.2 Ring gate -   50 Draft tube bend -   60.1, 60.2 Bypass pipe -   70.1, 70.2 Discharge pipe -   R Rotational axis 

1-11. (canceled)
 12. A hydraulic machine such as turbines or a pump or a pump turbine, comprising: a blade wheel which is rotatably mounted about a vertically disposed rotational axis (R) and comprises a plurality of blade wheels; an inlet spiral which surrounds the blade wheel in a ring-like manner and which comprises a circumferential outlet opening on its inner circumferential ring; a closeable guide and closure apparatus for controlling the inflow into the blade wheel, and a draft tube bend for guiding the water flowing out of the blade wheel, wherein the draft tube bend is arranged above the blade wheel, and at least one bypass pipe is provided for bypassing the guide and/or closure apparatus, which bypass pipe connects the inlet spiral directly to the blade wheel when a bypass valve is opened which is arranged in the course of said bypass pipe.
 13. A hydraulic machine with turbines or pump turbine, comprising a blade wheel which is rotatably mounted about a vertically disposed rotational axis (R) and comprises a plurality of blade wheels; an inlet spiral which surrounds the blade wheel in a ring-like manner and which comprises a circumferential outlet opening on its inner circumferential ring; a closeable guide and closure apparatus for controlling the inflow into the blade wheel, and a draft tube bend for guiding the water flowing out of the blade wheel, wherein the draft tube bend is arranged above the blade wheel, and at least one discharge pipe is provided for discharging the blade wheel, which discharge pipe connects the blade wheel directly to a pump sump when a discharge valve is opened which is arranged in the course of said discharge pipe.
 14. A hydraulic machine with turbines or pump turbine according to claim 12, wherein the at least one bypass pipe or the at least one discharge pipe preferably has a smaller pipe diameter than a ventilation pipe for venting or an aeration pipe for aerating the blade wheel
 15. A hydraulic machine with turbines or pump turbine according to claim 12, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into a lateral wheel space of the blade wheel.
 16. A hydraulic machine with turbines or pump turbine according to claim 12, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into an upper and/or bottom pump cover.
 17. A hydraulic machine with turbines or pump turbine according to claim 12, characterized by the arrangement of the pipe connections in the ring space between ring gate and guide apparatus.
 18. A hydraulic machine with turbines or pump turbine according to claim 17, characterized in that the guide apparatus for discharging/aerating or filling/venting is closed or is larger in an intermediate position than in the closed position.
 19. A method for filling a hydraulic machine with turbines or pump turbine according to claim 12, wherein the guide and/or closure apparatus is closed at first, whereupon at least one ventilation pipe is opened for venting the blade wheel and finally at least one bypass pipe is opened for bypassing the guide and/or closure apparatus, so that water can flow directly from the inlet spiral into the blade wheel and air can escape from the blade wheel.
 20. A method for discharging a hydraulic machine with turbines or pump turbine according to claim 13, wherein a closing valve on the high-pressure and low-pressure side is closed, whereupon an aeration pipe for aerating the blade wheel and finally at least one discharge pipe is opened for discharging the blade wheel, so that water can flow directly from the blade wheel to a pump sump.
 21. A method according to claim 19, wherein the bypass pipe or the discharge pipe is closed again after the filling or discharging of the blade wheel, and thereafter the ventilation pipe or the aeration pipe is closed again.
 22. The use of a hydraulic machine with turbines or pump turbine according to claim 12 in a pump storage power plant.
 23. A hydraulic machine with turbines or pump turbine according to claim 13, wherein the at least one bypass pipe or the at least one discharge pipe preferably has a smaller pipe diameter than a ventilation pipe for venting or an aeration pipe for aerating the blade wheel.
 24. A hydraulic machine with turbines or pump turbine according to claim 13, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into a lateral wheel space of the blade wheel.
 25. A hydraulic machine with turbines or pump turbine according to claim 14, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into a lateral wheel space of the blade wheel.
 26. A hydraulic machine with turbines or pump turbine according to claim 13, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into an upper and/or bottom pump cover.
 27. A hydraulic machine with turbines or pump turbine according to claim 14, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into an upper and/or bottom. pump cover.
 28. A hydraulic machine with turbines or pump turbine according to claim 15, wherein the at least one bypass pipe and/or the at least one discharge pipe opens into an upper and/or bottom pump cover.
 29. A hydraulic machine with turbines or pump turbine according to claim 13, characterized by the arrangement of the pipe connections in the ring space between ring gate and guide apparatus.
 30. A method according to claim 20, wherein the bypass pipe or the discharge pipe is closed again after the filling or discharging of the blade wheel, and thereafter the ventilation pipe or the aeration pipe is closed again.
 31. The use of a hydraulic machine with turbines or pump turbine according to claim 13 in a pump storage power plant. 